st: combining datasets with population weights

I would like to compare means and percentages of variables from a
small sample dataset to a large population national dataset. Both
datasets have the same variables. However, the population dataset has
population weights. I have stset the population dataset but I need to
combine the two datasets in order to run chi square analyses. I am
wondering how I can merge?/append? the two datasets but still apply
the population weights to the large dataset beforehand (and not apply
the population weights to the small sample).
Thanks for your help,
KS
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